Some air vehicles, such as unmanned air vehicles (UAVs) commonly operate with internal combustion engines. Consequently, when operating from higher elevations, the engine can suffer from reduced performance during flight due to the lesser available oxygen in the lower-density air in the surrounding environment, even when only attaining lower altitudes. Some UAVs are being adapted to operate with turbine engines to alleviate the performance problem of operation at higher elevations. Additionally, turbine engines provide other preferable performance characteristics, such as an increased thrust and durability.
Turbine engines, however, require more fuel when operating from lower elevations than at higher elevations. Because performance is directly related to the weight of the UAV and fuel is one of the largest contributors to the overall weight of the UAV, it is advantageous to manage the fuel aboard a UAV as precisely as possible. Some techniques of adjusting the fuel within a UAV's fuel tank include the use of metered fuel containers, graduated syringe fueling, fuel level sensors, and determination of fuel requirements in the field using air density/altitude lookup tables.
As different models and configurations of UAVs can have different performance characteristics, it can be difficult to compensate for altitude among various types of UAVs. Accordingly, because of the combination of different types of UAVs and varying elevations of operation, it can be problematic to optimize fueling of a UAV for a specific mission profile at a given elevation.